Both mammalian and nonmammalian species are used in biomedical research today. For various reasons, however, in recent years there has been increasing use of nonmammalian species. In 1985 the National Academy of Sciences issued a report describing the increasing trend in the use of non-traditional models for biomedical research (as reported by the Committee on Models for Biomedical Research in Models for Biomedical Research: A New Perspective, National Academy Press, Washington, DC, 1985). More recently, an in-depth discussion on the use of new models was given by Woodhead et al. in Nonmammalian Animal Models for Biomedical Research, CRC Press, Boca Raton, 1989. The description of nonmammalian animal model alternatives used in biomedical research emphasizes the emerging utility of these species with their specialized attributes. The species include fish, amphibians, birds and reptiles.
Reptiles (and more specifically arboreal reptiles) have recently emerged as animal models of considerable interest and potential. Although reptiles have not been commonly reported in previous biomedical literature, this status is changing, as may be noted by recent publications such as Callard I., ed. Unconventional Animal Models in Endocrine Research, Journal of Experimental Zoology 1990; In press and Greenberg N., Burghardt G. B., Crews D., Font E., Jones R. E., and Vaughan G. Reptile Models for biomedical research. In Woodhead A. D., and Vivirito K., eds. Nonmammalian Animal Models for Biomedical Research, CRC Press, Boca Raton, Fla., 1989. Thus, as noted in Greenberg, et al., it is now recognized "that several unique qualities of reptiles may provide models useful for research on a diverse array of problems of biomedical interest including developmental, endocrinological, neurological, and cellular aspects of stress and affective disorders, feeding, and reproductive dysfunction." It is known that reptiles are generally inexpensive, easily cared for and robust subjects to have as pet animals and possess unique abilities such as the ability for skin wounds to heal quickly even under less than aseptic conditions. As pet animals, or in zoos, they may be housed in everything from cardboard boxes to terrariums. When used in the biomedical research effort, however, caging criteria changes. Accordingly, there is a growing need for appropriate cages for use in housing such reptiles.
There are two branches of the Federal Government which regulate animal care and use in biomedical research: The U.S. Department of Agriculture (USDA) and the Department of Health and Human Services (DHHS).
The Animal Welfare Act, regulated by USDA, Animal and Plant Health Inspection Service, Laboratory Animal Welfare Act (PL89-544), US Government Printing Office, Hyattsville, Md., 1985, regulates care for animals to be used in various procedures. However, because reptiles are cold-blooded (poikilotherms), and not warm-blooded animals (homeotherms) they are not subject to the caging regulations of the Animal Welfare Act. Nonetheless, because they are vertebrates, reptiles fall within the definition of "animal" listed in the HHS Public Health Service Policy on the Humane Care and Use of Laboratory Animals, Revised 1986. Reptiles are thus subject to the requirements of the applicable regulations therein. It is noted that the Public Health Service Animal Welfare Policy uses the Guide for the Care and Use of Laboratory Animals, Committee on Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources, National Research Council, National Institutes of Health, Bethesda, MD. DHEW Publication No. 85-23, 1985, as its interpretation of animal care and use activities, including caging, animal social environment, and provides guidelines for appropriate macro and micro environments such as temperature, humidity, ventilation, illumination and the like.
The Guide was prepared for the more traditionally used laboratory animals in biomedical research such as dogs, cats, rodents, rabbits and non-human primates. Accordingly, the Guide does not specifically provide appropriate guidance for caging reptiles, and other nonmammalian vertebrates.
As reptiles are vertebrates, because they possess a backbone, appropriate caging for these species must be in accordance with the general principles identified in the Guide. Caging should be designed to meet research requirements, facilitate animal well-being and minimize experimental variables. The cage should, moreover, be appropriate in size for the species being housed and should be designed with the safety of both the animal and the handler taken into consideration.
Specifically, the Guide calls for caging to provide space that 1) is adequate and comfortable; 2) provides an escape-proof enclosure that confines animals safely; 3) provides easy access to food and adequate ventilation; 4) meets the biological needs of the animals including maintenance of body temperature, urination, defecation, and reproduction; 5) keeps the animals dry and clean; 6) avoids unnecessary physical restraint, and 7) protects the animals from hazards.
From a practical and versatile point of view, the cage should be mobile and be constructed of sturdy, durable materials and should be designed to minimize cross-infection between adjoining units. Moreover, the cost and ease of construction should be balanced with durability of the final product.
There is accordingly a need in the prior art to provide a cage meeting the above requirements and having particular applicability to reptiles, specifically to arboreal reptiles and potentially other small mammals, birds, and the like.
Other criteria of concern in providing a cage for appropriate housing of arboreal reptiles include a requirement for satisfying both the needs of the animal and those of the investigator, which often are opposite to one another. For example, from the point of view of the animal, the cage should provide a suitable temperature and humidity, must be hygienic, and must contain the right furnishings such as hide boxes, water bowls, branches for climbing and the like.
However, from the investigator's point of view, the cage should be secure, to prevent escapes, should be easy to clean (with minimal upset to the inhabitants thereof) and should provide some safety for the investigator when the cage is used to house potentially hazardous species such as those that are venomous or overly aggressive.
Each of these criteria create definite needs for specific cage structures to provide appropriate housing for such animals.
Many prior art attempts at providing various cages are known but have various difficulties associated therewith. Thus, it has been known to use glass aquaria, plastic kitchen tubs and cages constructed of wood and wire screen to house such animals. However, numerous problems are associated with such prior art designs, including the presence of broken glass or sharp edges, which may be harmful both to the animals and to the investigators. Further, decaying or warping wood construction and rusted metal fixtures can provide yet a further source of difficulty. Finally, most of these prior art designs are difficult to sanitize. To be in compliance with applicable Federal laws and regulations, this ability to sanitize is mandatory.
Various other cages are described in the patent literature as follows.
U.S. Pat. No. 3,815,549 to Opmeer discloses a bird cage having a pair of separable sections joined by an intermediate section, the sections being separable to improve maintenance. However, such a three-section cage is more difficult to construct and includes an open section at the top, thus failing to meet objectives for an all purpose housing apparatus.
U.S. Pat. No. 4,763,607 discloses a pet animal cage which includes clear plastic sides and a removable lid secured to the plastic sides by hook means. Suction cups are used to maintain the lid on the base. The cage is indicated as being useful for animals including snakes and lizards.
U.S. Pat. No. 4,526,133 to LoMaglio discloses an animal isolation cage ward which has a perforated metal top. The disclosed device provides upper and lower confinement units and separate doors, of transparent material, for each confinement unit. However, the device is intended primarily for use with small laboratory animals having infectious diseases and is intended for isolating the animals from one another. Accordingly, there is no provision for airflow from one unit to the other. Indeed, the two portions of the cage are two separate units rather than two portions of a single confinement unit separated by a slidable partition.
U.S. Pat. No. 4,480,587 discloses an animal cage utilizing a perforated metal top.
U.S. Pat. No. 3,225,738 discloses an animal cage and support which is provided with a removable floor divider as shown in FIG. 6.
Thus, none of the prior art teaches or suggests an acceptable cage for arboreal animals which meets or exceeds the various requirements for cages for arboreal animals, whether requirements established by regulation or by safety considerations, and the like.